Muse cells are one of the more interesting cell populations in regenerative medicine, and one of the more oversold in aesthetics. Identified by Mari Dezawa at Tohoku University in 2010, they are a rare SSEA-3-positive subpopulation making up roughly one to three percent of mesenchymal stromal cell cultures. What makes them unusual is the combination of properties: they are pluripotent-like and differentiate into all three germ layers without reprogramming, yet they show low telomerase activity and do not form teratomas the way embryonic and induced pluripotent stem cells do. They also home to injury through a genuine receptor mechanism, sensing sphingosine-1-phosphate released by damaged cells and following it via S1PR2, which is why they reach target tissue after intravenous delivery rather than being trapped in the lungs like ordinary MSCs. The clinical record is where the honest picture emerges. Human trials of the Japanese product CL2020 exist in subacute ischemic stroke, spinal cord injury, ALS, epidermolysis bullosa, myocardial infarction, and neonatal encephalopathy, totaling roughly 67 patients across six trials. Every single indication is serious disease. There are no clinical trials of Muse cells for any aesthetic purpose, and the marketed age-reversal claims rest on two case reports in which Muse cells were infused alongside exosomes and cord plasma, making attribution impossible. No Muse cell product is FDA-approved, and since Muse cells are a small minority of any MSC culture, an unsorted product without SSEA-3 verification is mostly not Muse cells at all. The biology deserves attention. The aesthetic market deserves scrutiny. This is educational, not medical advice. #MuseCells #RegenerativeMedicine #StemCellScience #AestheticMedicine #EvidenceBasedAesthetics Reference list 1. Kuroda Y, Kitada M, Wakao S, et al. Unique multipotent cells in adult human mesenchymal cell populations. Proc Natl Acad Sci USA. 2010;107(19):8639-8643. 2. Wakao S, Kitada M, Kuroda Y, et al. Multilineage-differentiating stress-enduring (Muse) cells are a primary source of induced pluripotent stem cells in human fibroblasts. Proc Natl Acad Sci USA. 2011;108(24):9875-9880. 3. Dezawa M. Macrophage- and pluripotent-like reparative Muse cells are unique endogenous stem cells distinct from other somatic stem cells. Front Bioeng Biotechnol. 2025;13:1553382. 4. Kuroda Y, Oguma Y, Hall K, Dezawa M. Endogenous reparative pluripotent Muse cells with a unique immune privilege system. Front Pharmacol. 2022;13:1027961. 5. Tanaka T, Nishigaki K, Minatoguchi S, et al. Muse cells home to damaged tissue via the S1P–S1PR2 axis. (Homing mechanism.) 6. Niizuma K, Osawa SI, Endo H, et al. Randomized placebo-controlled trial of CL2020, an allogenic Muse cell-based product, in subacute ischemic stroke. J Cereb Blood Flow Metab. 2023;43(12):2029-2039. 7. Fujita Y, Nohara T, Takashima S, et al. Intravenous allogeneic multilineage-differentiating stress-enduring cells in adults with dystrophic epidermolysis bullosa: a phase 1/2 open-label study. J Eur Acad Dermatol Venereol. 2021;35(8):e528-e531. 8. Safety and feasibility of intravenous administration of a single dose of allogenic Muse cells in human cervical traumatic spinal cord injury: a clinical trial. Stem Cell Res Ther. 2024. 9. Safety and clinical effects of a Muse cell-based product in patients with amyotrophic lateral sclerosis: results of a phase 2 clinical trial. Cell Transplant. 2023. 10. Safety and tolerability of a Muse cell-based product in neonatal hypoxic-ischemic encephalopathy with therapeutic hypothermia (SHIELD trial). Stem Cells Transl Med. 2024;13(11):1053. 11. The promising role of Muse cells in regenerative medicine: mechanisms, applications, and future directions. Life Sci. 2025. 12. Eggenhofer E, et al. Mesenchymal stem cells are short-lived and do not migrate beyond the lungs after intravenous infusion. Front Immunol. 2012;3:297.